1. Field
Exemplary embodiments of the present invention relate to an etching composition, a method of forming a metal pattern using the etching composition, and a method of manufacturing a display substrate. More particularly, exemplary embodiments of the present invention relate to an etching composition used for manufacturing a display substrate, a method of forming a metal pattern using the etching composition, and a method of manufacturing a display substrate.
2. Discussion of the Background
Generally, a display substrate used for a display device includes a thin-film transistor (“TFT”) as a switching element for driving each one of a plurality of pixel regions, a signal line connected to the TFT and a pixel electrode. The signal line includes a gate line transmitting a gate driving signal, and a data line crossing the gate line and transmitting a data driving signal.
As a size of the display device and a requirement of a customer for a high resolution are increased, a length of the gate line or the data line is increased and a width of the gate line or the data line is decreased so that an electric resistance is increased. Thus, a resistance-capacitance (“RC”) signal delay is caused, and then the gate line or the data line is formed from a metal having a relatively low resistance in order to solve the RC signal delay.
Copper as a metal having a relatively low resistance and used for forming the gate line or the data line has excellent electric conductivity and is a plentiful natural resource. In addition, copper has a resistance much lower than aluminum or chromium. In contrast, a resistance for an oxidizer of copper is higher than that of aluminum or chromium, so that a strong oxidizer may be used for etching a copper layer. Examples of a material that may be widely used for the strong oxidizer include hydrogen peroxide (H2O2) or iron (III) hydroxide (Fe(OH)3), etc. Korean Publication No. 2002-0050020 discloses a mixture of hydrogen peroxide, an inorganic acid or a neutral salt as an etchant for etching a copper layer, and Korean Publication No. 2005-0000682 discloses an etchant including hydrogen peroxide, a copper inhibitor, and hydrogen peroxide stabilizer and a fluoric ion. In addition, Korean Publication No. 2000-0032999 discloses a mixture of iron chloride 6-hydrate (FeCl3.6H2O) and hydrofluoric acid (HF).
However, although a copper etchant including the strong oxidizer such as hydrogen peroxide or iron (III) hydroxide effectively etches the copper layer, the copper etchant may damage patterns, which are formed prior to the copper layer, in the course of etching the copper layer. In addition, since the copper etchant includes the strong oxidizer, an etch rate of the copper layer is difficult to control so that the copper layer may be etched to have a shape different from a shape which is theoretically designed by a user.